Positron emission tomography (PET) is a powerful technology for medical and biological imaging and the scope of PET applications is expanding rapidly. The development of suitable PET tracers is critical to PET technology. An increasing number of PET tracers are peptide/protein based and are useful to specifically label tissues in therapeutic and/or diagnostic applications.
Fluorine-18 (18F) is a short-lived isotope of fluorine with suitable properties for PET-imaging. A majority of presently used radiopharmaceuticals in PET are labeled with fluorine-18. However, since the half-life of 18F isotope is only about 110 minutes, there is currently no facile and general method to efficiently and site-specifically modify proteins with 18F or other radionuclides in a short time period.